Security devices are necessary in order to prevent people from entering rooms or buildings which they are not authorized to enter and causing personal injury to occupants and committing theft. Most buildings use a locking door handle, or at most a deadbolt lock for this purpose. These locks suffice for many applications, but can be defeated by a sufficient force exerted against the door, causing the structure into which the deadbolt or locking latch extends to rupture, giving way to entry. Even if an alarm sounds notifying authorities, a person breaking into a building can usually remove some items from the building or harm the occupants and exit the premises before the authorities arrive.
In order to prevent the entry of any unauthorized people, devices have been conceived which attach to the door frame near opposite edges of a door, on the side of the door toward which the door opens, which provide greater resistance to the opening of the door than deadbolts and standard door latches.
In U.S. Pat. No. 4,067,598, Mansour provides a telescoping bar which fastens on one side of the door into the 2.times.4 framing of the door. The bar is pivotally attached to a bolt which extends into the framing, allowing the bar to pivot from a vertical position, where it can be stored without restricting the use of the door, to its horizontal position across the door. The bar fastens on the opposite side of the door to a locking fastener. A plurality of blocks of specified thickness are placed between the bar and the door to prevent substantial motion of the door.
One disadvantage of the Mansour invention is that a sufficient force exerted on the door will cause the bar to bend, allowing the distal end to slide horizontally out of the locking fastener and permit the opening of the door. Additionally, the mechanisms of the Mansour apparatus make it seem unsightly, which may prevent its use in residential applications. Furthermore, even if entry is prevented by the device, damage may be caused to the door due to the door pressing against the small blocks, or hitting against the narrow bar. Due to the small contact area between the door and the rod and blocks, the force of attempted entry may force the rod or blocks into the surface of the door. Because there is a lock on the fastening side, the further disadvantage exists of requiring that a key be kept available or a combination be remembered.
Another security device is shown in U.S. Pat. No. 4,974,889 to North. The apparatus consists of a cable covered by a sheath, and having one circular loop at each opposite end of the cable. A bolt having a circular opening at one end is fastened to the door framing on one side of the door with the opening exposed and pivotally attached to one loop of the cable. A second bolt having a hook at one end is fastened to the frame of the door on the opposite side from the first fastener and the second loop of the cable is removably fastenable to the hook.
The North apparatus has the disadvantage of being unattractive for some residential applications. For example, the cable is not removable from both fasteners, which means that it must hang, as shown in FIG. 5, near the door when not in use. Additionally, the narrow cable, although covered by a sheath, will probably mar the surface of the door during attempted forced entry. When the door is forced against the cable, the narrow cable will probably cut into the door at the point of contact.
Additionally, because the cable is made of metal fibers, there is little elasticity provided for reducing the shock of a force applied against the cable. A sharp blow to the door immediately applies a lateral force to the two fasteners, potentially jarring them loose enough from the framing members to permit their removal with another sharp blow.
The need exists for a security apparatus for extending across a door and fastening to a frame on opposite sides of the door which will not damage the door upon attempted entry, has some shock reducing characteristics to further prevent entry, and which may be removed from sight.